June, 1940] AGRICULTURAL RESEARCH IN N. H. 29 



The EfFect of Mulching on the Development of Bitter- Pit in Apples 



The results of chemical tests for available nutrients in small sam- 

 ples from the mulched and non-mulched trees taken in previous sea- 

 sons have shown that the soil under the mulch contained considerably 

 more available potassium than did that under the non-mulched trees. 

 In order to see whether the mulched trees were taking up any of 

 this additional potassium, leaf samples were taken at three different 

 dates. The June 7th samples showed no consistent difference but 

 both the July 17th and September 20th samples showed that the pet- 

 ioles of the mulched trees contained more extractable potassium 

 than did those from the non-mulched trees. Samples of soil have 

 been taken from beneath each tree in order to determine how far 

 the soluble organic matter from the decaying mulch has penetrated. 



The non-mulched trees last year, however, produced a higher per- 

 centage of large apples, reports O. R. Butler. The fruit was very 

 free from bitter-pit, only .03 per cent being found on the apples 

 from the non-mulched trees and .5 on the crop from the mulched 

 trees. In storage, the sample of fruit from mulched trees developed 

 8.62 per cent and the one from non-mulched trees 3.36 per cent bit- 

 ter-pit. (Purnell Fund) 



Effect of Place on Mosaic and Leaf-Roll 



Potatoes were grown in one series of experiments at a mean tem- 

 perature of 19.3° C. and in another series at a mean temperature of 

 i4.3°C. In the series grown at the higher temperature two types 

 of soil were used: 1. a light fertile loam (soil A); 2. a sandy 

 loam fr.om an old pasture (soil B). Finely ground peat was added 

 to each soil and the following fertilizer treatments were given. 



Soil A per plant: series 1, no fertilizer; series 2, 21 gms. 8-16-16; 

 series 3. 35 gms. 8-16-16. 



Soil B per plant: series 1, 150 gms. dry cow dung and 5 gms. 

 bone meal; series 2, 21 gms. 8-16-16; series 3, 28 gms. 8-16-16; 

 series 4, 35 gms. 8-16-16. Data were taken by O. R. Butler on the 

 rate of growth, and observations were made on the masking of 

 symptoms. In the plants fertilized with cow dung the general ap- 

 pearance of the series grown at 19^ and 14° C. respectively was very 

 similar and one had no difficulty in matching plants issued from the 

 same seed piece, even when grown at different temperatures. In 

 the fertilized series the plants grown at the higher temperature 

 showed less marked symptoms of mosaic than those groAvn at the 

 lower temperature and plants issued from the same seed piece could 

 not be matched with certainty. 



The nitrate nitrogen content of the soil was determined after the 

 the plants had grown for 34 days. The soil in the series fertilized 

 with cow dung contained very little nitrate, but in the series receiv- 

 ing chemical manure there were large amounts. High nitrate nitro- 

 gen depressed growth and yield. High nitrate nitrogen was more 

 injurious to the plants grown at 19° C. than to those grown at 14° C. 

 Between 40-50 parts per million of nitrate nitrogen produced highest 



